Device for loading catalyst into a reactor vessel

ABSTRACT

A device and method for loading catalyst pellets into reactor tubes of a chemical reactor. A direct mechanical force is applied to one or more pellets where bridging occurs that is different from the forces applied to the surrounding pellets in order to break up the bridge so as to allow catalyst particles to fall through an opening into the reactor tube.

This application claims priority from U.S. Provisional Application Ser.No. 61/347,483 filed May 24, 2010, which is hereby incorporated hereinby reference.

BACKGROUND

The present invention relates to a device for loading catalyst into thevertical reactor tubes of a chemical reactor.

Many chemical reactors are essentially a large shell and tube heatexchanger vessel, with the reaction occurring inside the tubes and acoolant circulating in the vessel outside the tubes. A chemical reactorvessel also can be a simple tank with a single volume of catalyst insideit, or it may be a single large tube. Some chemical reactions occur infurnace or reformer tubes, which may be a part of a system with 10 to500 or more such tubes. In any of these reactor vessels, catalyst,typically in the form of pellets (and other types of pellets that arenot catalyst), may be loaded into the reactor to facilitate thereaction. The pellets are replaced periodically.

The reactor tubes may be quite long, housed in a structure severalstories tall, and the pellets may be transported up several stories toan elevation above the top of the tubes so they may then flow by gravityinto the tubes. The pellets typically are supplied in 2,000 pound (orlarger) “super sacks”, 55 gallon drums, mini drums, metal bins orplastic bags loaded in pallet-mounted cardboard boxes.

The pellets are then carefully loaded into each reactor tube (there maybe several thousand tubes in a single reactor) to try to uniformly filleach tube. It is desirable to prevent bridging of the pellets in thereactor tube, because bridging can create voids or areas within a tubein which there are no pellets. Mechanical devices may be used to aid inthe loading of the pellets.

In some cases, in a shell and tube reactor in which vertical reactortubes are supported by upper and lower tube sheets, a template is placedover a portion of the upper tube sheet. The template has openingsaligned with the tops of the reactor tubes, with the openings in thetemplates having a smaller diameter than the inside diameter of thecylindrical reactor tubes in order to restrict the flow of pellets intothe reactor tubes to prevent bridging in the tubes. Pellets are dumpedon top of the template, and operators then use their gloved hands,paddles, brooms, or rakes to spread the pellets back and forth acrossthe template so that pellets fall through the holes in the template andinto the respective reactor tubes. Moving the pellets back and forthbreaks up any bridging of the pellets above the template, allowing thepellets to flow through the holes in the template and into the reactortubes.

In other instances, loading sleeves are inserted into each reactor tube,with each loading sleeve having a top opening that is smaller than theinside diameter of the cylindrical reactor tube in order to limit theflow of pellets to prevent bridging inside the reactor tubes. Again, thepellets are dumped on top of the loading sleeves, and the operators pushthe pellets back and forth across the loading sleeves so that thepellets fall through the holes in the loading sleeves and into therespective reactor tubes.

Various other loading techniques also are known, such as the methodtaught in U.S. Pat. No. 3,223,490 “Sacken”, in which a tray with aplurality of downwardly extending loading sleeves is placed directlyabove the tube sheet, with the loading sleeves extending into respectivereactor tubes. The catalyst is poured onto the tray, and then the trayis vibrated up and down vertically, shaking the pellets to break up anybridges and allow the pellets to fall through the sleeves in the trayand into the reactor tubes. The vibration of the pellets causes them torub against and impact against each other. Catalyst is a friablematerial and thus is brittle and readily crumbled. It is desirable tominimize the opportunity for the particles to rub against or impactagainst each other or otherwise to be abraded or crushed, because suchabrasion and crushing damages the pellets and creates dust. Raking thepellets back and forth across the template or loading sleeves createssubstantial abrading of the catalyst pellets, creating dust particleswhich may not only fall into the reactor tubes creating higher pressuredrops than desirable, but which also may become airborne, creating ahealth hazard for personnel inside the reactor vessel. Vibrating a trayfull of catalyst as in the Sacken arrangement also causes the pellets tobe jostled and to rub against and impact against each other, which alsoproduces similar results.

SUMMARY

The present invention relates to loading devices for loading pelletsinto reactor tubes which break up any bridging of the pellets by using asubtle, localized motion that imparts a direct mechanical force to atleast one of the pellets adjacent to the opening that is different fromthe force being applied to the surrounding pellets.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, section view of a shell and tube type of chemicalreactor vessel;

FIG. 2 is a plan view of the upper tube sheet of the reactor of FIG. 1;

FIG. 3 is a broken away, schematic section view of a single reactortube, tube sheet, and catalyst pellets, showing the pellets bridgingacross the top opening of the reactor tube;

FIG. 4 is a broken away, schematic section view, similar to FIG. 3, butshowing a much larger number of catalyst pellets bridging across the topopening of the reactor tube, and illustrates catalyst bridging inside areactor tube;

FIG. 5 is a broken away schematic section view, similar to FIG. 4, butwith the addition of a template to aid in the loading of the catalystpellets into the reactor tube;

FIG. 5A is a broken away schematic section view, similar to FIG. 5, butusing a loading sleeve instead of a template to aid in the loading ofthe catalyst pellets into the reactor tube;

FIG. 6A is a broken away, schematic plan view of a device for loadingcatalyst mounted over a portion of the template;

FIG. 6B is the same view as 6A, but with the device shifted to a secondposition;

FIG. 6C is the same view as 6B, but with the device shifted to a thirdposition;

FIG. 6D is a broken away, plan view of a portion of the catalyst loadingdevice of FIG. 6A, showing an alternate configuration for the openingsin the loading tray;

FIG. 7 is a broken away schematic section view, similar to that of FIG.5, but including the loading device of FIG. 6A in the position shown inFIG. 6A, with catalyst pellets bridging above the top of the reactortube;

FIG. 8 is the same view as 7, but showing the loading device in thesecond position, shown in FIG. 6B so as to break the bridging of thecatalyst pellets above the top of the reactor tube;

FIG. 9 is the same view as FIG. 8, but showing the loading device in athird position;

FIG. 10 is a schematic view of a pneumatic control arrangement for theloading device of FIGS. 6A-9;

FIG. 11 is a schematic section view of the loading tray, taken alongline 11-11 of FIG. 10;

FIGS. 12A-12H are schematic plan views of some of the possible motionswhich may be made by the loading device of FIG. 10;

FIG. 13 is a broken away, section view of another embodiment of aloading device for loading catalyst, mounted on an upper tube sheet;

FIG. 14 is a plan view of the loading device of FIG. 13, with the tubesheet omitted for clarity:

FIG. 15 is a broken away view, partially in section, of anotherembodiment of a device for loading catalyst;

FIG. 16 is a view taken along line 16-16 of FIG. 15;

FIG. 17 is a view taken along line 17-17 of FIG. 16;

FIG. 18 is a broken away section view of another embodiment of a loadingdevice;

FIG. 19 is a view taken along line 19-19 of FIG. 18;

FIG. 20 is view similar to FIG. 19, but for another embodiment of aloading device;

FIG. 21 is the same view of a loading tray as in FIG. 11 but showing analternate arrangement mounted on a tube sheet and including a spacerbetween the loading device and the tube sheet;

FIG. 22 is a broken away section view of the tube sheet, similar to FIG.3, except showing three tubes, each having a different height relativeto the tube sheet;

FIG. 23 is a side view of loading device like that of FIG. 11 or 21, butincluding a spacer to accommodate the varying tube heights of FIG. 22;

FIG. 24 is a side view of an alternate embodiment of a catalyst loadingdevice, shown in a first, lowered position;

FIG. 25 is a side view of the loading device of FIG. 24, shown in asecond, raised position;

FIG. 26 is a side view of another alternate embodiment of a catalystloading device, shown in a first position;

FIG. 27 is a side view of the catalyst loading device of FIG. 27, shownin a second position;

FIG. 28 is a plan view of an alternate embodiment of a catalyst loadingdevice, similar to that of FIG. 26, but having two bridge breakingwires;

FIG. 29 is a plan view an alternate embodiment of a catalyst loadingdevice, similar to that of FIG. 26, but for handling multiple tubessimultaneously;

FIG. 30 is a side view of the catalyst loading device of FIG. 29;

FIG. 31 is a side view of another embodiment of a catalyst loadingdevice;

FIG. 32 side view of a bin transport device for the catalyst loadingdevice of FIG. 31;

FIG. 33 is a plan view of one the bins of FIG. 31;

FIG. 34 is a side view of the bin of FIG. 33;

FIG. 35A is a side view of the bins of FIG. 31 and the bin transportdevice of FIG. 32, in preparation for transferring catalyst into thebins;

FIG. 35B is a side view, similar to FIG. 35A, but with the bin transportdevice starting to empty the catalyst into the bins;

FIG. 35C is a side view, similar to FIG. 35, but with the catalyst inthe bin transport device emptied into the bins;

FIG. 36 is a side view of another embodiment of a catalyst loadingdevice;

FIG. 37 is a view along line 37-37 of FIG. 36;

FIG. 38 is a broken away, side view, along line 38-38 of FIG. 36;

FIG. 39A is a section view along line 39A-39A of FIG. 38;

FIG. 39B is a section view along line 39B-39B of FIG. 38; and

FIG. 40 is a side view, similar to that of FIG. 38, but with the bridgebreaking device in the raised position.

DESCRIPTION

FIG. 1 depicts a typical chemical reactor vessel 10, which is a shelland tube heat exchanger, having an upper tube sheet 12 and a lower tubesheet 14 with a plurality of vertical tubes 16 welded or expanded to thetube sheets 12, 14 to form a tightly packed tube bundle. There may befrom one to many hundreds or even thousands of cylindrical tubes 16extending between the tube sheets 12, 14. Each tube 16 has a top endadjacent the upper tube sheet 12 and a bottom end adjacent the lowertube sheet 14, and the tubes 16 are open at both ends, except that theremay be a clip at the bottom end to retain catalyst pellets inside thetube. The upper and lower tube sheets 12, 14 have openings that are thesize of the outside diameter of the tubes 16, with each tube 16 locatedin its respective openings in the tube sheets 12, 14.

The vessel 10 includes a top dome (or top head) 13 and a bottom dome (orbottom head) 15, as well as manways 17 for access to the tube sheets 12,14 inside the vessel 10. The manways are closed during operation of thereactor but are opened for access, such as during catalyst handling. Inthis instance, the tubes 16 are filled with catalyst pellets, whichfacilitate the chemical reaction. (It may be noted that similarly-shapedshell and tube heat exchangers may be used for other purposes, such asfor a boiler or other heat exchanger.)

This particular reactor vessel 10 is fairly typical. Its tubes may rangein length from 5 feet to 65 feet, and it is surrounded by a structuralsteel skid or framework (not shown), which includes stairways orelevators for access to the tube sheet levels of the reactor vessel 10as well as access to intermediate levels and to a topmost level whichmay be located at or near the level of the top opening of the reactorvessel 10. On a regular basis, which can be every 2 to 48 months orlonger, as the catalyst becomes less efficient, less productive, or“poisoned”, it is changed out, with the old catalyst being removed and anew charge of catalyst being installed in the tubes 16 of the reactorvessel 10. Catalyst handling also may have to be done on an emergencybasis, on an unplanned and usually undesirable schedule.

A catalyst change operation involves a complete shutdown of the reactor,resulting in considerable cost due to lost production. (The loadingdevices shown and described herein may be used both for the initialloading of a new reactor and for catalyst change operations.) It isdesirable to minimize the amount of time required for the catalystchange operation in order to minimize the lost production andaccompanying cost caused by the reactor shutdown.

FIG. 2 is a schematic plan view of the upper tube sheet 12 of FIG. 1,including a plurality of reactor tubes 16 (and is identical to the lowertube sheet 14). As shown in FIG. 3, catalyst pellets 18 may bridge overthe open top end of the reactor tube 16 when trying to load catalystinto the reactor tube 16, which prevents the pellets from entering intothe reactor tube 16. FIG. 4 shows that the bridging situation isexacerbated as more catalyst pellets 18 are dumped on top of the tubesheet 12. Furthermore, if two or more pellets 18 fall into the topopening of the reactor tube at approximately the same time, theconditions are favorable for forming a bridge inside the reactor tube16, as shown in FIG. 4, which creates a void or space below the bridgedcatalyst inside the tube 16, preventing the catalyst from completelyfilling the reactor tube 16 and resulting in a non-uniform andundesirable catalyst loading of the reactor tube 16.

To prevent bridging of catalyst pellets 18 inside the reactor tube 16,prior art devices have relied on templates 20 (as shown in FIG. 5) orloading sleeves 22 (as shown in FIG. 5A) which have smaller openings 34(in FIG. 5) and 23 (in FIG. 5A) than the reactor tubes 16 and therebyrestrict the flow of pellets 18 into the reactor tubes 16 so as toprevent bridging inside the tube 16. (i.e., if the pellets flow throughthe tube 16 in “single file” or few enough at a time that they cannotspan the full diameter of the tube at any one time, bridging will notoccur.) However, the catalyst pellets 18 still form natural bridges atopthe template 20 or atop the loading sleeve 22. Operators sweep the moundof catalyst pellets 18, as depicted by the arrow 25 in FIGS. 5 and 5A,using gloved hands, paddles, brooms, rakes, and other such devices tobreak the bridging so that additional catalyst pellets 18 fall throughthe openings 34 in the template 20 (or through the openings 23 in theflanges 21 of the loading sleeves 22) and drop into the reactor tubes16. This sweeping action is applied to substantially the entire mass ofcatalyst pellets 18 resting atop the template 20 or loading sleeves 22,causing many of the brittle catalyst pellets 18 to fracture and breakinto smaller particles and forming dust.

FIGS. 6A-D and 7-10 show an arrangement including a first embodiment ofa catalyst loading device 24 for loading catalyst into reactor tubes.The loading device 24 rests on top of a template 20, which rests on topof the upper tube sheet 12 of the reactor 10. On the right side of FIG.6A are shown some of the openings 34 in the template 20, and, behindthem in phantom are the open-top reactor tubes 16. While the drawingshows only some of those openings 34 and tubes 16, it is understood thatthe openings 34 and tubes 16 are distributed evenly throughout thetemplate 20 and the upper tube sheet 12, respectively. (This may bebetter understood by looking at FIG. 11, which is a section view throughthe tray 26 only.) It should be noted that the openings 34 in thetemplate 20 have a smaller diameter than the inside diameter of thereactor tubes 16 and are axially aligned with the tubes 16. The template20 is a relatively thin body having horizontal, planar top and bottomsurfaces and defining a plurality of holes extending from the topsurface to the bottom surface. The bottom surface of the template 20rests on top of the upper tube sheet 12 and may cover all or a portionof the upper tube sheet 12.

As best appreciated in FIG. 6A, the catalyst loading device 24 includesa tray 26, which is operatively connected, via connecting rods 28 andpivots 30 (pivot locations are located on the rod end and cap end oftheir respective cylinders), to four linear-motion drives 32, which arefixed in position by means of pins 33, which extend into reactor tubes16, as shown in FIGS. 7-9. (They could extend into other openings in thetube sheet 12 or in the template 20, or be secured in position by othermeans, if desired.) The double headed arrows 31 indicate the directionof motion of the linear-motion drives 32. The pivots 30 at either end ofeach connecting rod 28 allow for misalignment in the connection betweenthe linear-motion drives 32 and the tray 26 to permit the desired motionof the tray 26. The tray 26 moves substantially horizontally, along aplane which is parallel to the plane of the template 20 on which thetray 26 rests. The tray 26 includes means for holding a plurality ofpellets and has a plurality of openings 36 through which the pelletsmust pass in order to flow from the tray into the respective verticalreactor tubes 16. The pellets also must pass through the openings 34 inthe template 20 located below the tray 26 in order to flow into therespective reactor tubes 16.

Again, while only some of the openings 36 are shown, it is understoodthat the openings 36 are evenly distributed over the entire tray 26.

In an alternative arrangement, the catalyst loading device 24 may reston top of the flanges 21 of a plurality of loading sleeves 22 (See FIG.5A) instead of resting on top of the template 20. In that case, then thepellets also would pass through the openings 23 in the loading sleevesin order to flow into the respective reactor tubes 16.

As shown in FIGS. 6A-D and 7-9, the tray 26 of the catalyst loadingdevice 24 is resting on top of the template 20. The openings 36 throughthe tray 26 are a bit larger than the corresponding openings 34 in thetemplate 20, which permits the tray 26 to shift horizontally relative tothe stationary template 20 without closing off any portion of theopenings 34 in the template 20.

As shown in FIGS. 6A and 7, the openings 36 of the tray 26 are axiallyaligned with the openings 34 in the template 20, which, in turn, areaxially aligned with the respective longitudinal axes of the reactortubes 16. The template 20 lies between the tray 26 and the tube sheet12. Some of the pellets 18 that are forming a bridge are in contact withthe top surface of the template 20.

As shown in FIGS. 6B and 8, the tray 26 has been shifted to the left, sothe axes of the openings 36 in the tray 26 are to the left of the axesof their respective template openings 34 and reactor tubes 16. Thisposition is achieved by the linear-motion drives 32 on the right handside of the catalyst loading device 24 (as seen from the vantage pointof FIGS. 6A-C) pushing the tray 26 to the left. This causes the verticaledge of the opening 36 in the tray 26 to contact the pellet 18A, whichis resting on the top surface of the template 20 and push it to theleft, into the opening 34 of the template 20, so that pellet 18A fallsthrough the openings 36 and 34 and into the reactor tube 16. Since thepellet 18A was supporting the bridge adjacent to the opening 36, itsmovement relative to the other pellets 18 causes the bridge to fall andallows other pellets 18 to fall through the openings 36, 34 into thereactor tube 16 until another bridge is formed adjacent to the opening36.

As the linear-motion drives 32 on the right hand side of the catalystloading device 24 (as seen from the vantage point of FIGS. 6A-C) pullthe tray 26 to the right while at the same time the linear-motion drives32 on the bottom of the catalyst loading device 24 (as seen from thevantage point of FIGS. 6A-C) pull the tray 26 to the bottom, the largerthrough openings 36 of the catalyst loading device 24 are also shiftedto the right and bottom, but are still in fluid communication with therespective top openings 38 of the reactor tubes 16 via the smallerthrough openings 34 of the template 20. This corresponds to FIGS. 6C and9.

As was explained briefly above, it can be seen in FIG. 7 that a bridgehas been formed above the reactor tube 16, and some of the catalystpellets 18 are resting on the template 20 inside the opening 36 of thetray 26. When the tray 26 is shifted to the left, the edge of theopening 36 of the tray contacts one or more of those pellets 18A,shifting it to the left as well, which breaks up the bridge and allowspellets 18 to fall through the opening 36 in the tray and through theopening 34 in the template 20 into the reactor tube 16 until anotherbridge forms adjacent to the opening 36 in the tray 26.

Shifting the tray 26 to the position of FIG. 9 causes the edge of theopening 36 to contact another pellet 18B, again shifting that pellet 18Bto break up the bridge that it is supporting and allowing the pellets 18to fall through the openings 36, 34 in the tray 26 and template 20,respectively, and into the open top 38 of the reactor tube 16 untilanother bridge is formed.

This movement of the tray 26 relative to the template 20 continues topush the supporting pellets out from under the bridge of pellets thatthey are supporting, thereby breaking up the bridges and allowing thepellets to flow into the reactor tubes 16 without causing any morejarring or abrading of the pellets than is needed to break up thebridging and allow the pellets to flow through the tray 26 into thereactor tubes 16.

FIGS. 12A-12H schematically depict some of the different paths which maybe traced out by the tray 26, ranging from a circular clockwise orbit(FIG. 12A); a circular counter-clockwise orbit (FIG. 12B); quartercircle turns (ninety degrees) alternating clockwise and counterclockwise(FIG. 12C); shorter arcuate turns (such as 45 degrees) alternatingclockwise and counterclockwise (FIG. 12D); quarter oval-shaped turnsalternating clockwise and counterclockwise (FIG. 12E); rectangularorbits (FIG. 12F); star-shaped orbits (FIG. 12G); and hexagonal-shapedorbits (FIG. 12H). These different paths are just some of those whichmay be traced out by the tray 26, depending on the control scheme forthe catalyst loading device 24. A possible control scheme is shown inFIG. 10 and described below. FIG. 6D depicts an alternate shape for theopening 36′ in the tray 26′ of the loading device 24′, showing thatthese openings 36′ need not be round (as shown in FIGS. 6A-6C) nor dothey have to correspond on a one-to-one basis with the openings 34 inthe template 20 (or in the loading sleeve 22). In this instance, theopenings 36′ are almost triangular in shape, with each opening 36′ ofthe tray 26′ opening into three openings 34 in the template 20.

The control system described in FIG. 10 involves driving the loadingdevice 24 pneumatically. It includes four linear-motion pneumatic drives32, each one connected to the tray 26 via its corresponding connectingrod 28. A pivot 30 at each end of each connecting rod 28 ensures thatthe connection point at the tray 26 may be misaligned from theconnection point at the linear-motion drive 32 so as to permit thedesired motion of the tray 26.

A source 40 of pressurized gas (such as compressed air) is in fluidcommunication, through piping 42, 44, with two multi-port solenoidvalves 46, 48. Each solenoid valve 46, 48 is in turn in fluidcommunication with two linear-motion pneumatic drives 32 through a setof four flow control devices as described in more detail below.

The operation of the control scheme for the catalyst loading device 24of FIG. 10 is described below with respect to one linear-motion drive 32only, on the upper left hand corner of FIG. 10. It will be clear thatthe other drives 32 operate in essentially the same manner. The airsource 40 provides compressed gas to the solenoid valve 46 via the line42. The solenoid valve 46 sends the compressed air via the path 50 tothe line 52 and through the flow control limiter 54 to the linear-motiondrive 32 which pushes the connecting rod 28 outwardly (in the downdirection as seen from the vantage point of FIG. 10). The air isexhausted through the flow control limiter 56 and through the line 58back to the solenoid valve 46 which exhausts the air through the path60. A proximity switch 62 on the linear-motion drive 32 sends a signalto a controller (not shown) when the linear-motion drive 32 has reachedthe end of its run. The controller actuates the solenoid valve 46,causing it to shift to a second position (not shown), which reverses theflow of compressed air to retract the connecting rod 28 on thelinear-motion drive 32. The proximity switch 62 on the linear-motiondrive 32 again sends a signal to the controller when the linear-motiondrive 32 has once again reached the end of its run. The controlleractuates the solenoid valve 46 which shifts and again reverses the flowof compressed air, and the entire cycle is repeated.

While air-operated drives 32 are described here, it is understood thatthe drives could be electric motors or other known drive means instead,and the control means would be suitable to control the drive means.

Operation of the Catalyst Loading Device

The catalyst loading device 24 is placed atop a template 20 wherein thethrough openings 34 on the template 20 are substantially axially alignedwith the reactor tubes 16. Preferably the linear-motion drives 32 of thecatalyst loading device 24 are secured to the template 20 or to the tubesheet 12 to prevent any relative movement between the linear-motiondrives 32 and the template 20. Catalyst pellets 18 are dumped into thetray area 26 of the catalyst loading device 24 which is then powered upto begin the catalyst loading process. The relative horizontal motionbetween the tray 26 and the template 20 breaks any bridges as they form,allowing the catalyst pellets 18 to fall through the respective opening36 in the tray 26 and opening 34 in the template 20 and into the reactortubes 16, as shown in FIGS. 6A-9.

It should be noted that during this process there is very littlejostling and relative motion between the vast majority of the catalystpellets 18 in the tray 26. When a local bridge is broken and a catalystpellet 18 falls through the template 20 and into a reactor tube 16, anycatalyst pellets 18 immediately above the collapsed bridge will collapseas well and flow into the tube 16 until a new bridge is formed. This newbridge is then broken by the relative motion between the tray 26 and thetemplate 20, and the process is repeated continuously until the reactortube 16 is fully loaded, or the tray 26 runs out of catalyst pellets 18,or the catalyst loading device 24 is powered off. Not only is there verylittle relative motion among the catalyst pellets 18 in the tray 26,which limits the erosion and breakage of the catalyst pellets 18 and theconsequent dust generation, but the whole process is mechanized andneeds very little operator attention.

Of course, as explained earlier, the catalyst loading device 24 may reston top of the flanges 21 of a plurality of loading sleeves 22 (see FIG.5A) instead of resting on top of the template 20, in which case theoperation would be the same.

Note that it is the relative motion between the tray 24 and theunderlying substrate (such as the surface of the template 20 or thesurface of the flange of the loading sleeve 22) that imparts a directmechanical force to at least one of the pellets 18 adjacent to theopening 36 that is different from the forces being applied to the othersurrounding pellets 18 in order to break up the bridging adjacent to theopening 36, allowing catalyst pellets 18 to fall out of the tray 26,through the openings 36 and 34, and into the reactor tube 16. Thisprocess continues repeatedly, with successive bridge forming followed bybridge breaking to load the reactor tube 16 with catalyst pellets 18.

Additional Embodiments of a Catalyst Loading Device

FIGS. 13 and 14 show another embodiment of a catalyst loading device 70.Comparing this catalyst loading device 70 in FIG. 13 with the loadingsleeve 22 of FIG. 5A, it may be seen that they are quite similar. Themost obvious difference is that the catalyst loading device 70 ismechanically driven by a drive 72 via a belt 74. The drive 72 may be arotary or articulating drive, and the belt 74 is a means fortransferring the motion of the drive 72 to the loading sleeve 76 of thecatalyst loading device 70, as best seen in FIG. 14. This means fortransferring the motion of the drive 72 to the loading sleeve 76 may beaccomplished by a variety of other means (not shown) such as a gear or arod.

A less obvious difference is the presence of ridges 78 on the topsurface of the flange 80 of the loading sleeve 76. This embodiment showstwo ridges 78 (See FIG. 14) which extend radially from the opening 77 tothe outer edge of the flange 80 and which are diametrically opposed fromeach other. While the ridges 78 are preferred, the flange 80 may have aroughened surface or other high friction surface that will cause apellet 18 that is resting on the top surface of the flange 80 to movealong with the flange 80.

As may be seen in yet another embodiment of a catalyst loading device70* in FIG. 16, the loading sleeve may have one or more such ridges 78,78*, as described in more detail later. The ridges 78, 78* serve toenhance the frictional resistance between the flange 80 of the loadingsleeve 76 and the catalyst pellets resting atop the flange 80 of theloading sleeve 76, such that the mechanical motion imparted by the drive72 to the loading sleeve 76 is more readily transmitted to the catalystpellets resting atop the flange 80 so as to promote the breaking of anycatalyst bridge.

In this embodiment, the drive 72 imparts a rotary motion to the loadingsleeve 76 of the catalyst loading device 70, causing the flange 80 ofthe loading sleeve 76 to rotate in a horizontal plane, parallel to thetop of the tube sheet 12, rotating slowly about its longitudinal axis,which is a vertical axis, aligned with the vertical axis of the reactortube 16. As it does so, the catalyst pellets 18 resting directly on topof the flange 80 travel with the flange 80, so the flange 80 imparts adirect mechanical force to the pellets 18 resting on top of it, causingthem to move relative to the other surrounding pellets 18 above them,which breaks up any catalyst bridges that may form just above thereactor tube 16. In this case, the tube sheet 12 provides means forholding a plurality of pellets above the vertical reactor tube 16. Theopening 77 in the flange 80 has a smaller diameter than the insidediameter of the reactor tube 16, and the pellets pass through theopening 77 to flow through from the holding means into the reactor tube16.

FIGS. 15-17 depict yet another embodiment of a catalyst loading device70*. This is similar to the catalyst loading device 70 of FIGS. 13 and14, except that the drive 72* is anchored and substantially enclosed byan adjacent reactor tube 16.

In FIG. 15, only the tube sheet 12 is shown in section. The drive 72*includes a battery 82*, a motor 84*, and a gearbox 86*, all of which aresuspended inside a reactor tube 16 by the flange 88* which rests atopthe tube sheet 12. A pulley 90* is engaged by the belt 74* which in turnengages and drives a similar pulley 92* on the loading sleeve 76*. Inthis embodiment of a catalyst loading device 70*, the loading sleeve 76*includes a bearing housing 94* and a bearing 96* to minimize frictionalresistance to rotation of the loading sleeve 76* in the reactor tube 16.

The flange 80* on the loading sleeve 76* defines a plurality of ridges78*(See also FIGS. 16 and 17). As the drive 72* rotates the loadingsleeve 76*, the flange 80* imparts a direct mechanical force to thepellets resting on it, causing those pellets to shift relative to therest of the pellets in the bridge, and thereby breaking up any bridgingof pellets adjacent to the opening 77* in the flange 80* so the pellets18 can flow through the opening 77* and into the reactor tube 16.

FIG. 18 depicts yet another embodiment of a catalyst loading device70**. In this embodiment, the catalyst loading device 70** includes twoloading sleeves 76** (though one or more such loading sleeves 76** maybe present) which are similar to the loading sleeve 76 of FIGS. 13 and14 in that they includes ridges 78**. This catalyst loading device 70**rests on top of an elevated stationary template or frame 98** which hasa top surface that lies on a plane which is parallel to the plane of thetop surface of the tube sheet 12, but which provides some clearancebetween the frame 98** and the tube sheet 12. The loading sleeve 76**has its flange portion 80** resting on top of the frame 98**, while itstubular “leg” portion 100** extends through the frame 98**, through thespace between the frame 98** and the tube sheet 12, through the tubesheet 12, and into the reactor tube 16. The flange 80** defines anopening 23** that has a smaller diameter than the inside diameter of thereactor tube 16, again in order to regulate the flow of catalystparticles into the reactor tube 16 to prevent bridging within the tube16.

Mounted to the leg portion 100** of the loading sleeve 76**, and in thespace between the frame 98** and the tube sheet 12, are blades 102**(See also FIG. 19), similar to the blades of a blower fan. A compressedair nozzle 104** is mounted to the frame 98**. As seen in FIG. 19, asthe compressed air from the air nozzle 104** blows on the blades 102**of the loading sleeve 76**, it applies a force causing the loadingsleeve 76** to rotate in the direction of the arrow 106. The compressedair from the air nozzle 104** may blow continuously or it may blowintermittently to cause the loading sleeve 76** to spin about itslongitudinal axis, and as it does so, it imparts a direct mechanicalforce to the pellets 18 resting on top of the flange 80** of the loadingsleeve 76** which moves the catalyst pellets 18 resting directly atopthe flange 80** relative to other pellets 18 that may be forming abridge adjacent to the opening 23** in the flange 80** to break up anycatalyst bridges, allowing catalyst to fall through the opening 23** inthe loading sleeve 76**.

FIG. 18 also shows a funnel-like container 108** directly above theloading sleeve 76**, which provides means for holding a plurality ofpellets 18. This container 108** may include a mark 110** correspondingto a preset volumetric loading of catalyst inside a reactor tube. Inthis embodiment, the funnel-like container 108** does not rotate withthe loading sleeve 76**, but remains stationary, resting on thestationary frame 98**. This embodiment may be particularly useful forpartial loading of reactor tubes, such as when reactor tubes are loadedwith different types of catalyst to different heights within the reactortubes.

FIG. 20 is a view similar to FIG. 19, but for yet another embodiment ofa catalyst loading device. This catalyst loading device is essentiallyidentical to the catalyst loading device 70** of FIG. 18, except that ithas a different mechanism for rotating the loading sleeve 76′. In thisinstance, the loading sleeve 76′ is rotated by means of a drive (notshown) similar to the drive 72 of FIGS. 13 and 14, via a belt 74′ and apulley 75′. Of course, other drive means, such as gears or rods, may beused instead of a belt.

Each loading sleeve 76** in FIG. 18 (or 76′ in FIG. 20) may beindividually driven, or several may be tied together to a common drive.For instance, the belt 74′ in FIG. 20 may wind over a number of pulleys75′ of different loading sleeves 76′. Likewise, the air nozzle 104** maybe fed by a common compressed air line manifold which supplies air to aplurality of air nozzles which blow air on other catalyst loadingdevices 70**.

It sometimes occurs that the top tube sheet 12 in a reactor vessel isnot completely flat. Sometimes it is very slightly domed and often, asshown in FIG. 22, the reactor tubes 16 project upwardly beyond the toptube sheet 12, with some tubes projecting upwardly more than othertubes. In FIG. 22, the upper portion 16A projects upwardly more than theupper portion 16 b. Some tubes may have a plug 114 secured to the topportion, as shown with the top portion 16 c, which causes the tube toproject even a greater distance above the tube sheet 12.

FIG. 21 shows a solution to the problem of an uneven tube sheet 12,whether because the tube sheet 12 is slightly domed or because the tubes16 project upwardly and unevenly from the tube sheet 12. In thisinstance, a spacer 112 is installed between the tube sheet 12 and thetemplate 20 (or it could be between the tube sheet 12 and the loadingsleeves 22 of FIG. 5A). This spacer 112 is preferably made of a foammaterial which adapts its shape to conform to the dome shape of the tubesheet 12. The spacer 112 has through openings 116 which are aligned withthe reactor tubes 16 in the tube sheet 12. These openings 116 are largeenough to accommodate any tube projections above the tube sheet 12 suchthat the top surface 118 of the spacer 112 is substantially flat despiteany unevenness in the tube sheet 12 and its reactor tubes 16.

FIG. 23 shows an alternate solution to the problem of an uneven tubesheet 12. In this instance, the template 20 is supported above the tubesheet 12 via a plurality of legs 120, with the openings 34 in thetemplate 20 substantially vertically aligned with the top openings ofthe reactor tubes 16.

FIGS. 24 and 25 show another embodiment of a catalyst loading device122. This catalyst loading device 122 is similar to a loading sleeve,such as the loading sleeve 22 of FIG. 5A in that it includes tubularvertical leg 124, a portion of which slides into the top of a reactortube 16. It also includes a flange 126 which supports the catalystloading device 122 on the top surface of the tube sheet 12, and it has athrough opening 128 at the top of the vertical leg 124 with a smallenough diameter to restrict the flow of catalyst particles into thevertical leg 124 and into the reactor tube 16 so as to prevent possiblebridging inside the vertical leg 124 and the reactor tube 16.

The catalyst loading device 122 includes a funnel shaped container 129which provides means for holding a plurality of pellets above thereactor tube. This funnel 129 is attached to, and supported by, thevertical leg 124 of the loading sleeve by a plurality of archedstringers 130. This arrangement allows a narrow annular clearance 136between the top edge 134 of the vertical leg 124 and the bottom opening136 of the funnel 129, which is just wide enough for a movable sleeve132 to fit between the vertical leg 124 and the funnel 129 and to shiftup and down, as explained in more detail below.

The movable sleeve 132 has an inside diameter which is just slightlylarger than the outside diameter of the vertical leg 124 of the loadingsleeve and an outside diameter that is just slightly smaller than theinside diameter of the bottom edge 136 of the funnel 129. A lower stopband 138 is secured to the outside surface of the vertical leg 124 toprovide a lower stop for the movable sleeve 132, as shown in FIG. 24. Anupper stop band 140 is secured to the outside surface of the movablesleeve 132 to provide an upper stop for the movable sleeve 132, as shownin FIG. 25, wherein the upper stop band 140 impacts against the bottomof the funnel 129 to stop the movable sleeve 132 at its upper limit.

It may be appreciated that, when the movable sleeve 132 is in its lowestposition, as shown in FIG. 24, the top edge 131 of the movable sleeve132 is substantially flush with the top edge 134 of the vertical leg124. However, when the movable sleeve 132 is moved to its raisedposition as shown in FIG. 25, the top edge 131 of the movable sleeve 132projects above the top edge 134 of the vertical leg 124 and into thefunnel area itself. This slight vertical movement of the movable sleeve132 relative to the top edge 134 of the vertical leg 124 imparts adirect mechanical force to the pellets 18 adjacent to the opening 128that is different from forces being applied to the surrounding pelletsin order to break up any bridging that may occur within the funnel 129adjacent to the opening 128.

To use the catalyst loading device 122, the leg 124 of the loadingsleeve is inserted into a reactor tube 16 until the flange 126 isresting on top of the tube sheet 12. Note that the flange 126 may beadjusted vertically along the vertical leg 124, as desired by looseningthe adjustment screw 127, shifting the flange 126 to the desiredposition, and then tightening the adjustment screw 127. Catalystparticles (not shown) are added to the funnel 129, and the movablesleeve 132 is moved up and down to continuously break any bridge formingadjacent to the opening 128 of the loading sleeve. The movable sleevemay be moved manually or by some type of automated mechanism asdescribed with respect to the loading device 122* of FIG. 36. Thisprocess continues repeatedly, with successive bridges forming and thenfollowed by bridge breaking to load the reactor tube 16 with catalystpellets. As is explained below with respect to another embodiment of acatalyst loading device 122*(See FIG. 36), the vertical movement of themovable sleeve 132 may be mechanized to automate the loading of catalystinto the reactor tubes 16.

FIGS. 36-40 show another embodiment of catalyst loading device 122*. Itis similar to the catalyst loading device 122 of FIG. 24 in that it hasa funnel 129*, a flange 126*, a vertical leg 124*, a stop 138*, and athrough opening 128*(See FIG. 37) at the top of the vertical leg 124*which has a small enough diameter to ensure that the flow of catalystparticles is restricted enough to prevent bridging in the leg 124* andin the reactor tube 16.

Referring to FIGS. 37, 38, 39A, and 39, the stop 138* is actually asleeve or collar which includes a ring 139* with three upwardly andinwardly projecting prongs 142*. The prongs 142* are parallel to eachother, have their top edges at the same elevation, their bottom edges atthe same elevation, and are spaced apart at 120 degree intervals. Theprongs 142* ride in grooves 144*(See FIG. 38) in the vertical leg 124*.These grooves 144* extend from the top edge 146* of the vertical leg124* downwardly to a distance substantially equal to the height of theprongs 142*, as seen in FIG. 38. The grooves 144* lie inside theperimeter of the funnel 129*, so, as the collar 138* moves upwardly, theprongs 142* move up into the interior of the funnel 129*. The collar138* can move upwardly until its ring 139* abuts the outer surface ofthe funnel 129*, and it can move downwardly until the bottom surfaces148* of the prongs 142* abut the surfaces 150* at the bottom of thegrooves 144*(unless the drive mechanism prevents the collar 138* fromreaching its upper and lower limits).

When the sleeve 138* is in its lowered position, as seen in FIGS. 38,39A, and 39B, the bottom surface 148* of the prong 142* rests on top ofthe surface 150* at the bottom of the groove 144*(see FIG. 39B), and thetop surface 152* of each prong 142* is flush with the top edge 146* ofthe vertical leg 124*(as shown in FIGS. 36, 37, and 38).

When the sleeve 138* is raised, as seen in FIG. 40, the top surface 152*of each prong 142* projects upwardly into the funnel area. This verticalmovement of the prongs 142* of the sleeve 13* allows the prongs 142* toimpart a direct mechanical force to the pellets 18 adjacent to theopening 128* that is different from the forces being applied to thesurrounding pellets in order to break up any bridging that may occurwithin the funnel 129* adjacent to the opening 128*. Therefore, thiscatalyst loading device 122* works in a very similar manner to thecatalyst loading device 122 described earlier.

FIG. 36 shows an actuator 152 that is fixed relative to the vertical leg124* and that is functionally connected to the collar 138* via aconnecting rod 154. The actuator 152 imparts a linear, up-and-downvertical motion to the connecting rod 154, which, in turn, imparts thesame motion to the collar 138*, as illustrated by the arrow 156, inorder to automate the bridge breaking function of the catalyst loadingdevice 122*.

FIGS. 26 and 27 show yet another embodiment of a catalyst loading device122**. This catalyst loading device 122* includes a vertical leg 124**and a funnel 129** which holds the pellets above the reactor tube. Thetop edge 134** of the vertical leg 124** defines a through opening 128**with a smaller diameter than the rest of the leg 124** and a smallerdiameter than the inside diameter of the reactor tube 16 into which theleg 124** is inserted to control the flow rate of pellets in order toprevent bridging in the leg 124** and in the reactor tube 16. A shortdistance above the top edge 134** of the vertical leg 124** (thatdistance preferably being less than the smallest dimension of thepellets 18), a rod 156** projects through the sides of the funnel 129**and extends substantially across and over the opening 128**. The rod156** may be a stiff rod or wire, or it may have some flexibility suchas may be obtained by using a thin plastic strip. A small enlargement orbump 158** is located midway along the length of the rod 156**. As therod 156** reciprocates horizontally back and forth in the motionindicated by the arrow 160, the enlargement 158** moves across theopening 128** and imparts a direct mechanical force to at least one ofthe pellets adjacent to the opening 128** that is different from forcesbeing applied to the other surrounding pellets in order to break up anybridges formed by the catalyst pellets adjacent to the opening 128**.This process continues repeatedly, with successive bridge formingfollowed by bridge breaking to load the reactor tube with catalystpellets. The rod 156** may be moved manually or through an automated,reciprocating mechanism such as a linear actuator that is fixed relativeto the leg 124**.

FIG. 28 is a plan view of another embodiment of a catalyst loadingdevice 122′. This catalyst loading device 122′ is identical to thecatalyst loading device 122** described above, except that it has tworods 162′, 164′ extending through the funnel 129′ instead of the singlerod 156** described earlier. It should be noted that neither of thesetwo rods 162′, 164′ is located directly above the centerline of thethrough opening 128′ through which the catalyst pellets fall into thereactor tube 16. The rod or rods should be located close enough to theopening 128′ to impart a direct mechanical force to at least one of thepellets adjacent to the opening 128′ that is different from the forcesapplied to the other surrounding pellets in order to break the bridgesformed adjacent to the opening 128′.

It should also be noted that the bumps 158** and 158′ in the rods arenot strictly necessary for proper operation of the catalyst loadingdevices. They provide enhanced contact between the rod and the catalystpellets and in this manner improve the bridge breaking characteristicsof the device. Other means for enhancing the contact with the pellets18, such as roughening of the rod itself, may be used for the same endresult.

FIG. 28 further shows a reciprocating rotary actuator 166 used toautomate the reciprocating motion of the rods 162′, 164′ in thedirection of the arrow 160′. Though not shown in this view, the actuator166 may be used to reciprocate rods connected to a plurality oflinearly-aligned catalyst loading devices 122′.

FIGS. 29 and 30 show another embodiment of a catalyst loading device122″. This catalyst loading device 122″ may be described as a hybridbetween the catalyst loading device 24 of FIG. 6A and the catalystloading device 122** of FIG. 26. The catalyst loading device 122″includes a tray 26″ with a plurality of through openings 36″, similar tothe tray 26 (See FIG. 11) of the catalyst loading device 24. The arrow168 (See FIG. 29) indicates the reciprocating motion of the tray 26″ tobreak any catalyst bridges by the tray 26″ imparting a direct mechanicalforce to pellets resting on the underlying substrate within the openings36″ of the tray 26″. The underlying substrate is not shown in this view,but has been identified earlier with respect to the description of thecatalyst loading device 24, as being either a template or a plurality ofloading sleeves.

A comparison of the tray 26 of FIG. 11 with the tray 26″ of FIGS. 29 and30 shows the addition of stationary rods 170 with resistance enhancingbumps 172 to the catalyst loading device 122″, similar to the rod 156**and bump 158** of the catalyst loading device 122** of FIG. 26. Thereciprocating motion of the tray 26″ relative to the stationary rods 170(as indicated by the arrow 168) causes the rods 170 to impart a directmechanical force to the pellets adjacent to the openings 36″ that isdifferent from the forces applied to the surrounding pellets in order tobreak up catalyst bridges adjacent to the openings 36″.

FIGS. 31-35 show yet another embodiment of a catalyst loading device122^. This catalyst loading device 122^ is similar to the catalystloading device 24 of FIG. 6A, but it has several separate bins mountedon the loading tray 12^ so a measured load of catalyst pellets 18 isdelivered into each reactor tube 16.

Referring to FIG. 31, and comparing it with FIG. 6A, the catalystloading device 122^ includes a tray 26^ with a plurality of openingsthat are generally aligned with the openings in the top of the reactortubes 16. It differs from the embodiment of FIG. 6A in that there areseveral bins 176 mounted on the tray 26^. The openings in the tray 26^are the same size as and are aligned with the openings 190 in thebottoms of the bins 176, and the tray 26^ is thin enough that theopenings in the tray are effectively the same as the openings 190 in thebottoms of the bins 176.

As with the embodiment of FIG. 6A, this embodiment includes a pluralityof linear motion drives 32^ that impart a reciprocating motion to thetray 26^ (and to the bins 176 that are fixed relative to the tray 26^).

Referring to FIGS. 33 and 34, each loading bin 176 is a container havinga generally rectangular cross-section with an open top 178, four sidewalls 180, 182, 184, and 186, and a bottom with sloping ramps 188 thatdirects catalyst pellets to the through opening 190 (which correspondsto the opening 36 in the tray 26 of FIG. 6A). Alternatively, each bin176 may have an open bottom which matches up directly with itscorresponding loading plate 174 which is part of the loading tray 26^,and these loading plates 174 that have the sloping ramps 188 directcatalyst pellets to the through openings 190.

The cross-section of the loading bin 176 is large enough relative to thesize of the catalyst pellets that the pellets will not bridge in the bin176 until they reach the bottom of the bin 176 adjacent the opening 190.Any bridging in the bin 176 will occur at the very bottom of the bin176, just above the opening 190. Just as with the embodiment of FIG. 6Aas described earlier, the reciprocating motion of the tray 26^ willimpart a direct mechanical force to the pellets resting on the templatebelow the tray 26^ that is different from the force being applied tosurrounding pellets, thereby causing relative motion between the pelletsforming a bridge so as to break up the bridges and allow the pellets tofall through the openings 190 and into the reactor tubes 16.

This catalyst loading device 122^ has a yoke 192 that projects above thebins 176, as shown in FIGS. 31 and 34, which assists with loading thecatalyst pellets into the bins 176, as will now be described.

With this embodiment, catalyst pellets are delivered in catalysttransport devices 196, which are open top containers that are adjustablymounted together on a transport bar 198 as shown in FIG. 32 such thattheir positions along the length of the transport bar 198 may beadjusted to match the location and spacing of the loading bins 176. Thetransport bins 196 may be sized as needed. An exact, measured charge orload of catalyst pellets 18 (See FIGS. 35A-35C) is loaded into eachtransport bin 196 outside of or adjacent to the reactor prior to theloading operation. This charge may be measured by volume, by weight, orby some other desired means. In this particular embodiment, thetransport bins 196 have marking lines 197 at various elevations, whichindicate the various volume charges of pellets that would be loaded intothe transport bin 196 if the pellets reached the particular marking line197.

There are spools 200 mounted on the loading bar 198, and these spoolsrest on the yokes 192 of the loading bins 176. The spools 200 aid in theproper alignment of the transport bins 196 with the respective loadingbins 176 and provide a bearing surface to support the transport bins 196on the yokes 192. There also are handles 202 mounted on the transportbar 198 to assist the operators in pivoting the transport bins 196 toempty the catalyst pellets 18 into the respective loading bins 176, asshown in FIGS. 35B and 35C.

Initially, a measured charge of catalyst pellets 18 is loaded into eachof the transport bins 196 (See FIG. 35A). This preferably is doneoutside of the reactor 13 (See FIG. 1). A plurality of these catalysttransport bins 196 may be used such that some of them are being loadedwhile others are being used to transport catalyst to the catalystloading device 122^, or the catalyst pellets may be delivered to thesite pre-measured and pre-loaded into the transport bins 196.

The transport bins 196 may be picked up by the operators and transferredinto the reactor vessel 13 through the manhole 17 for fixed headreactors or onto the reactor tube sheet area for removable head reactorseither individually or in groups that are already mounted on a transportbar 198. Referring to FIG. 35A, the catalyst transport bins 196, mountedon the transport bar 198, are moved in the direction of the arrow 204,and placed onto the catalyst loading device 122^ such that the spools200 rest on the yokes 192, which automatically aligns the transport bins196 with the loading bins 176, as shown in phantom. The operators thenpivot the transport bar 198 in the direction shown by the arrows 206,208 of FIG. 35B until all the catalyst pellets 18 are emptied from thetransport bins 196 into their respective loading bins 176, as shown inFIG. 35C.

Once the catalyst is loaded into the loading bins 176, the transport bar198 with attached transport bins 196 is removed and the motion drives32^ are powered up to start the reciprocating motion of the tray 26^ andof the loading bins 176 that are fixed to the tray 26^. Note that thecatalyst loading device 122^ is mounted on a template 20, or on aplurality of loading sleeves 22, or may even be mounted directly on thetube sheet 12. If no template or loading sleeves are used, the openings190 should be small enough to control the flow rate of pellets into thereactor tubes 16 to prevent bridging inside the reactor tubes 16.

The reciprocating motion of the catalyst loading device 122^ imparts aforce to at least one of the pellets resting on the template 20 orloading sleeve 22 or tube sheet 12 that is different from the forcebeing applied to the surrounding pellets in order to break up anybridging in the loading bins 176 adjacent to the openings 190 to keepthe catalyst pellets 18 flowing into the respective reactor tubes 16.This process continues repeatedly, with successive bridge formingfollowed by bridge breaking to load the reactor tubes 16 with catalystpellets 18.

It should be noted that the speed of the reciprocating motion of thecatalyst loading device 122^ may be adjusted as desired to achieve thedesired flow of pellets through the loading device 122^ and into thereactor tubes 16.

It will be obvious to those skilled in the art that modifications may bemade to the embodiments described above without departing from the scopeof the present invention.

What is claimed is:
 1. A method for loading pellets into a verticalreactor tube in a chemical reactor, wherein the vertical reactor tubehas an inside diameter and extends downwardly from a horizontal uppertube sheet, comprising the steps of: providing a first body includingmeans for holding a plurality of pellets above the reactor tube; loadinga plurality of pellets onto the first body; defining a first openingthrough which the pellets pass in order to flow from the first body intothe vertical reactor tube, said first opening having a smaller diameterthan the inside diameter of the vertical reactor tube; and imparting adirect mechanical force to at least one of the pellets adjacent to thefirst opening that is different from forces being applied to thesurrounding pellets in order to break up any bridging that may occurwithin the pellets lying above and adjacent to the first opening;wherein imparting said direct mechanical force includes providingrelative movement in the horizontal direction between said first bodyand a second body located adjacent to the first opening; wherein thefirst body is a tray, the second body defines a horizontal surfacelocated directly below the tray, and wherein the pellet to which thedirect mechanical force is applied is resting on the horizontal surfaceof the second body.
 2. A method for loading pellets as recited in claim1, wherein the second body is stationary with respect to the reactortube and the tray moves relative to the second body.
 3. A method forloading pellets as recited in claim 2, wherein the second body is atemplate.
 4. A method for loading pellets as recited in claim 2, whereinthe second body is a loading sleeve including a flange which defines thehorizontal surface.
 5. A method for loading pellets as recited in claim2, wherein the second body is the upper tube sheet.
 6. A method forloading pellets as recited in claim 1, wherein the tray includes aplurality of separate loading bins, each of said loading bins definingan interior that communicates with an opening in the tray.
 7. A methodfor loading pellets as recited in claim 6, and further comprising thestep of loading a plurality of transport bins with a predefined amountof pellets and then dumping the pellets from the transport bins intorespective loading bins.
 8. A method for loading pellets as recited inclaim 6, and further comprising the step of loading each of a pluralityof transport bins with a predetermined volume of pellets, wherein eachof the transport bins has markings at various elevations indicatingvarious volumes.
 9. A method for loading pellets as recited in claim 2,wherein the second body defines the first opening and the tray defines asecond opening having a larger diameter than the first opening, whereinthe pellets first pass through the second opening in the tray and thenthrough the first opening and then into the reactor tube.
 10. A methodfor loading pellets as recited in claim 6, wherein the opening in thetray is said first opening.
 11. A method for loading pellets, into avertical reactor tube in a chemical reactor, wherein the verticalreactor tube has an inside diameter and extends downwardly from ahorizontal upper tube sheet, comprising the steps of: providing a firstbody including means for holding a plurality of pellets above thereactor tube; loading a plurality of pellets onto the first body;defining a first opening through which the pellets pass in order to flowfrom the first body into the vertical reactor tube, said first openinghaving a smaller diameter than the inside diameter of the verticalreactor tube; and imparting a direct mechanical force to at least one ofthe pellets adjacent to the first opening that is different from forcesbeing applied to the surrounding pellets in order to break up anybridging that may occur within the pellets lying above and adjacent tothe first opening; wherein the step of imparting a direct mechanicalforce to at least one of the pellets adjacent to the first openingincludes providing relative movement in the horizontal direction betweenthe first body and a second body located adjacent to the first opening;wherein the second body is a loading sleeve which has a horizontalflange that moves relative to the first body.
 12. A method for loadingpellets as recited in claim 11, wherein the first body is the upper tubesheet.
 13. A method for loading pellets as recited in claim 11, whereinthe first body is a template.
 14. A method for loading pellets, into avertical reactor tube in a chemical reactor, wherein the verticalreactor tube has an inside diameter and extends downwardly from ahorizontal upper tube sheet, comprising the steps of: providing a firstbody including means for holding a plurality of pellets above thereactor tube; loading a plurality of pellets onto the first body;defining a first opening through which the pellets pass in order to flowfrom the first body into the vertical reactor tube, said first openinghaving a smaller diameter than the inside diameter of the verticalreactor tube; and imparting a direct mechanical force to at least one ofthe pellets adjacent to the first opening that is different from forcesbeing applied to the surrounding pellets in order to break up anybridging that may occur within the pellets lying above and adjacent tothe first opening; wherein the step of imparting a direct mechanicalforce to at least one of the pellets adjacent to the first openingincludes providing relative movement in the horizontal direction betweenthe first body and a second body located adjacent to the first opening;wherein the second body is a reciprocating rod.
 15. A method for loadingpellets, into a vertical reactor tube in a chemical reactor, wherein thevertical reactor tube has an inside diameter and extends downwardly froma horizontal upper tube sheet, comprising the steps of: providing afirst body including means for holding a plurality of pellets above thereactor tube; loading a plurality of pellets onto the first body;defining a first opening through which the pellets pass in order to flowfrom the first body into the vertical reactor tube, said first openinghaving a smaller diameter than the inside diameter of the verticalreactor tube; and imparting a direct mechanical force to at least one ofthe pellets adjacent to the first opening that is different from forcesbeing applied to the surrounding pellets in order to break up anybridging that may occur within the pellets lying above and adjacent tothe first opening; wherein the step of imparting a direct mechanicalforce to at least one of the pellets adjacent to the first openingincludes providing relative movement between the first body and a secondbody located adjacent to the first opening; wherein the second bodyreciprocates up and down relative to the first body.
 16. A method forloading pellets as recited in claim 15, wherein the second body includesa collar that reciprocates up and down along a loading sleeve thatextends into the reactor tube.